A Study to Evaluate Effectiveness and Safety of ER OROS Paliperidone in Patients With Schizophrenia

• Change From Baseline in Positive and Negative Syndrome Scale (PANSS) - Positive Subscale Score [ Time Frame: Baseline and 6 weeks ] [ Designated as safety issue: No ]
  The PANSS Positive Subscale assesses seven positive-symptoms of schizophrenia. Positive symptoms refer to an excess or distortion of normal functions. The symptoms are rated on a 7-point scale, with a range of 7 (absent) to 49 (extreme psychopathology).
• Change From Baseline in Positive and Negative Syndrome Scale (PANSS) - Negative Subscale Score [ Time Frame: Baseline and 6 weeks ] [ Designated as safety issue: No ]
  The PANSS Negative Subscale assesses seven negative-symptoms of schizophrenia. Negative symptoms represent a diminution or loss of normal functions. The symptoms are rated on a 7-point scale, with a range of 7 (absent) to 49 (extreme psychopathology).
• Change From Baseline in Positive and Negative Syndrome Scale (PANSS) - General Psychopathology Subscale Score [ Time Frame: Baseline and 6 weeks ] [ Designated as safety issue: No ]
  The PANSS General Psychopathology Subscale Score assesses 16 general psychopathology symptoms. The symptoms are rated on a 7-point scale, with a range of 16 (absent) to 112 (extreme psychopathology).
• Proportion of Responders (≥30% Decrease in Total Positive and Negative Syndrome Scale [PANSS]) [ Time Frame: Baseline and 6 weeks ] [ Designated as safety issue: No ]
  Responders are subjects with 30% or more reduction from baseline in total PANSS score. PANSS is a medical scale that assesses various symptoms of schizophrenia. The symptoms are rated on a 7-point scale from 1 (absent) to 7 (extreme psychopathology). The total score is the sum of all 30 PANSS items, with a range of 30 (absent) to 210 (extreme ill).
• Change From Baseline in Clinical Global Impression Scale (CGI-S) [ Time Frame: Baseline and 6 weeks ] [ Designated as safety issue: No ]
  The CGI-S rating scale is a 7-point global assessment with scores as follows: 1 - Not ill, 2 - Very Mild, 3 - Mild, 4 - Moderate, 5 - Marked, 6 - Severe, and 7 - Extremely Severe.

The purpose of this study is to evaluate the effectiveness and safety of Extended Release Osmotic Controlled-Release Oral Delivery System (OROS) Paliperidone compared to placebo in patients with Schizophrenia. Olanzapine will be used as a reference drug in the study.

This is a multicenter, double blind (neither the patient nor the physician knows whether drug or placebo is being taken, or at what dosage), randomized (patients are assigned different treatments based on chance), placebo- and active-controlled, parallel-group study. Patients will be randomized into 1 of 3 treatment groups to receive oral dosages of Extended Release (ER) Osmotic Controlled-Release Oral Delivery System (OROS) paliperidone 6 mg, olanzapine 10 mg, or placebo. They will receive two capsules of Paliperidone ER 3 mg, placebo or Olanzapine 5 mg once daily after breakfast for 6 weeks. The study will include a screening period, followed by double-blind treatment for 6 weeks.

• Drug: ER OROS paliperidone
  Type= exact number, unit= mg, number= 3, form= tablet, route= oral use. Two tablets once daily for 6 weeks.
• Drug: Placebo
  Form= tablet, route= oral use. Two tablets once daily for 6 weeks.
• Drug: Olanzapine
  Type= exact number, unit= mg, number= 2.5, form= tablet, route= oral use. Four tablets once daily for 6 weeks.

• Experimental: ER OROS paliperidone
  Extended Release (ER) Osmotic Controlled-Release Oral Delivery System (OROS) paliperidone
  Intervention: Drug: ER OROS paliperidone
• Placebo Comparator: Placebo
  Intervention: Drug: Placebo
• Active Comparator: Olanzapine
  Intervention: Drug: Olanzapine

Inclusion Criteria:

• Patients who have given their own consent in writing to participate in the study
• Patients diagnosed with schizophrenia according to the diagnostic criteria of DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 295.30, 295.10, 295.20, 295.90, 295.60)
• Patients who have acute symptoms of schizophrenia
• Both inpatients and outpatients are acceptable

Exclusion Criteria:

• A DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) of a mental disease diagnosis other than schizophrenia
• A DSM-IV diagnosis of substance-related disorder (except nicotine dependence and caffeine dependence) within 180 days before the screening test
• Total PANSS (Positive and Negative Syndrome System) score at the screening test <70 or >120
• Patients treated with three or more types of antipsychotic within 28 days before the screening test
• Parkinson's disease (except for those with drug-induced extra pyramidal symptoms)
• Patients with a complication of or a past history of cerebrovascular accident
• Patients with a complication of or a past history of diabetes mellitus